It is worse than this Daniel. Multiplexed is where many servers are on one tape. It basically single threads the restores. They do have a feature like TSM for SAP that uses multiple tape drives to span the data across. There TSM and NetBackup are pretty equal, when it works.
The big deal with incrementals in NetBackup is you have to figure it all out. It is not automatic. At least our folks never figured it out. -----Original Message----- From: Daniel Sparrman [mailto:[EMAIL PROTECTED]] Sent: Thursday, April 18, 2002 6:36 AM To: [EMAIL PROTECTED] Subject: Re: Veritas/Legato/ArcServ Hi Using incrementals on Veritas Netbackup has a disadvantage; it slow down restores. There is support cases at Veritas confirming that when using incremental backups, restore times can take up to 10 times normal time. The solution for this, according to Veritas, is to use full backups instead of incremental. And, when using multiplexing, the restore won't go that much faster. Netbackup still has to do a partial restore;first the full backup, then the incrementals. This is not a effective way of doing restores... Best Regards Daniel Sparrman ----------------------------------- Daniel Sparrman Exist i Stockholm AB Propellervägen 6B 183 62 HÄGERNÄS Växel: 08 - 754 98 00 Mobil: 070 - 399 27 51 "Seay, Paul" <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 2002-04-18 05:28 Please respond to "ADSM: Dist Stor Manager" To: [EMAIL PROTECTED] cc: Subject: Re: Veritas/Legato/ArcServ I can speak to Veritas NetBackup. You are correct that a tape is created for each full and incremental, but there is a feature in NetBackup that allows you to multiplex the server saves to a single tape up to a limit you specify. This really great until you try to duplicate the tapes for offsite storage. The duplications tape literally exponentially longer as the number of files gets larger. We found it quicker to run the full backup twice than to duplicate the tapes. The backup involved ran for about 20 hours on a full to get the two copies. This was using Magstar tape and Shark disk, big file system on a high end UNIX SGI machine. The real issue is NetBackup supports the original and a duplicate only. It supports 9 retention periods only. It does not have a deleted file policy, so once the tapes expire the data is gone. It is tape expiration oriented instead of object. It has a tape catalog and what files are on the tapes. When you do an incremental restore there is no directory structure rebuild, meaning that files that have been deleted are restored, so the concept of put the system at point in time does not exist. This can play havoc with applications using touch files to signal application progressing. You talk about more tapes, but more tapes also means more tape drives to process. There is no disk pool concept in NetBackup. It is written directly to tape, period. This is where TSM eats NetBackups Breakfast, Lunch, Dinner and Midnight Snack. We took a 12 Magstar drive NetBackup windows environment using about 180K of NT hardware and migrated it to TSM using 6 drives and a AIX P660. Nothing else changed except it freed up 6 high end NT servers. Instead of running a few of our 108 servers each night on full backups and round robin throughout the week, no C: drive backups, no point in time restore capability, duplicates often late getting offsite, only 2 weeks of recover, we now have a primary, onsite copy, offsite copy and sit around joking about the days of the NetBackup debacle we extracated. The company is about to adopt a daily offsite strategy. Thank you TSM for making it a possibility. Plain and Simple. NetBackup is extremely expensive to run. The maintenance on the software is much higher than TSM, it costs more than TSM, it uses at least twice as much hardware as TSM, has horrible support, and just plain does not scale. -----Original Message----- From: Gabriel Wiley [mailto:[EMAIL PROTECTED]] Sent: Wednesday, April 17, 2002 1:46 PM To: [EMAIL PROTECTED] Subject: Re: Veritas/Legato/ArcServ Gerald, I use to work with Veritas, and I may soon be back in that boat..(not by chioice) You are correct , we wasted a lot of tape.. And the quick recovery time was dependant on the Offsite vendor returning our media.. We set up our clients in different classes(TSM's version of stgpools & schedules) they would dump their data to "the" diskpool and copy would take place soon after. At the time we didn't have a way to collocate so the data could span multiple tapes.. (Don't know what that is like today) If client a needed a restore, client x,y and z's data would have to return in order for us to get all the required data restored for client a .. But this was a couple years ago~ Gabriel C. Wiley ADSM/TSM Administrator AIX Support Phone 1-614-308-6709 Pager 1-877-489-2867 Fax 1-614-308-6637 Cell 1-740-972-6441 Siempre Hay Esperanza Gerald Wichmann <[EMAIL PROTECTED] To: [EMAIL PROTECTED] OM> cc: Sent by: "ADSM: Subject: Veritas/Legato/ArcServ Dist Stor Manager" <[EMAIL PROTECTED] .EDU> 04/17/2002 01:19 PM Please respond to "ADSM: Dist Stor Manager" Not specifically TSM question but more of a question to better understand how to discuss pro's/cons to other competing products. Since my background is all TSM, I'm curious on how the other competitors handle media. Is my assumption correct that they waste a lot of tape space? As far as I understand it, all these products do traditional full/incremental type backups where each full and incremental "uses a tape". Thus Server 1 would suck up 7 tapes in a week (1 full, 6 incrementals). Is this true? Or can these products actually put 2 full's on a single tape? Or multiple incrementals on a single tape?
